Mapping (Almost) Every Tree In Central Park"Central Park—before it was Central Park—was a desolate, rocky swamp," birdwatcher Ken Chaya says. Now, he and an author have mapped almost 20,000 trees in the New York City arboretum.

Now a story of how a couple of men who love trees have created a map of almost every one of the more than 20,000 trees in Central Park. It's called "Central Park Entire," and it took Edward Barnard and Ken Chaya's two-and-a-half years to create.

Chaya walked thousands of miles in the park, not only mapping the trees but even dirt trails that had been put on a map before.

NPR's Margot Adler reports.

MARGOT ADLER: We're sitting on a bench in the northern part of Central Park, where some of the oldest trees live. Edward Barnard is 75 years old. He points out tree species.

Mr. EDWARD BARNARD (Author, "New York City Trees"): There's a London Plane down there. There's the pignut hickory that we were talking about.

ADLER: The two of them quickly name about 30 species as they sit. Barnard is the author of "New York City Trees," but while working on the book he realized he needed a real map of all the trees in the park. So he teamed up with Ken Chaya, a long-time Central Park birder.

Barnard became Chaya's tree mentor. As a birder, Chaya thought what could be so hard, the trees don't move. But as he became obsessed with the project, the park became totally new for him.

Mr. KEN CHAYA (Central Park Birder) It was like learning how to see new colors, or textures. The park never looked the same again once I began to discover the many, many species of trees.

ADLER: We come across the stumps of two red oaks that were probably here before the park was created in 1857 by Frederick Law Olmstead and Calvert Vaux. They fell during a storm two years ago. You can count 150 rings on one, but it's decades older than that, they say, because the center is rotted out.

Mr. CHAYA: And so I love to imagine Vaux and Olmsted, standing here and saying, say, look at those two lovely young red oaks, maybe they'll be nice and big one day and we'll plan the path around them.

ADLER: The map is 26 by 36 inches and waterproof. There's a poster version as well; 19,933 trees are placed in their correct positions, 174 species in all. I ask Chaya to point out on the map the exact trees we're standing under. He points to two leaf-shaped marks.

Mr. CHAYA: That represents the twin sweetgums that we're standing under, and the symbol here for the sweetgum replicates the shape of the leaf pretty closely.

ADLER: There's a slightly different shape for each species, and there are some color differences, but it's challenging; they're pretty similar.

Mr. CHAYA: It's not easy to distinguish between 174 different small green shapes. I believe the map, like nature itself, is really meant to be studied.

ADLER: He advises taking along a tree guide as well. Of course, nature doesn't stand still. We look across a stream to the stump of a large pin oak. It was standing when the map was published a couple of weeks ago. Already the map is a little out of date. They know there will have to be updates.

Walking through the wildflower meadow, Barnard and Chaya say there's a secret treasure. We duck under leaves and suddenly we are in a hidden world under a huge American beach that you can't even see from the meadow.

No one would even know this is here.

Mr. CHAYA: It's like standing in a green tent, underneath this tree, and right now there's no one else here. It's quiet.

ADLER: This was a labor of love for them, and they got no funding for creating the map. As Chaya spent more time in the park, he began to see its design.

Mr. CHAYA: Olmsted used trees the way an artist uses colors. He used them to create curtains, walls, corners, and the design itself, it looks natural. Many people think this is what Manhattan looked like before Central Park. Well, Central Park before it was Central Park was a desolate, rocky swamp.

ADLER: But birds drop seeds, new trees come up, some cross-pollinate. This environment is constantly shaped.

Mr. CHAYA: By the birds that arrive every spring, every fall, by the plants and trees that proliferate, by summer storms and winter snows.

ADLER: Made by humans, shaped by nature. Perhaps the best free arboretum you can find, and now there's even a map.

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